The tunnel resistor

Nonlinear load resistors in high-speed tunnel-diode computer circuits offer several advantages over conventional linear load resistors, namely reduced power dissipation and therefore higher packing density, increased switching speed and relaxed tolerances on the power supplies. Such resistors have been constructed by combining a tunnel-diode junction with tunneling leakage paths on the surface of the same semiconductor junction using a metal plating technique. The plated metal, which on the average is less than monoatomically thin, forms conducting islands through which tunneling takes place in parallel with the tunneling across the junction. The added conductance is in itself nonlinear. The resulting characteristic exhibits a plateau where the current is substantially independent of voltage over a range of 50-100mv. The parallel resistance applied in this manner is free of the spurious reactances usually connected with resistances applied outside or on the surface of the encapsulation of the tunnel diode, and therefore allows stable operation up to very high frequencies. At the same time the application method allows the necessary very close control of the characteristics of the resulting combination. Results are presented using Ge, GaAs and Ga Sb and include information on radiation tolerance and life tests.